The present invention relates to the field of medical devices for conducing close range physical medical examinations, in particular to colposcopes used for conducting gynecological and urological examinations.
Two methods are used for earlier detection of cervical cancer and pre-cancer: cytology and colposcopy. Cytology is a screening method that is practical and economical, while colposcopy is a diagnostic method for clinical diagnosis of patients with abnormal cytology. Each method has its practical limitations and strength in cancer detection, and both methods complement each other.
Currently a standard gynecological exam comprises the use of a speculum, visual examination of the vaginal interior cavity and related structures without any use of magnification, pulpation of the pelvic region and a Pap smear. If the abnormalities are not detected visually, they may be detected by the Pap smear or Pap test. The word xe2x80x9cPapxe2x80x9d is short for Papanicolaou, which is the last name of the doctor who studied earlier detection of changing cervical cells. When conducting Pap smear screenings, the gynecologist gently scrapes and collects exfoliated cells from the surface of the cervix by a thin wooden stick and a tiny brush and places them on slides that are sent to a cytologist for further examination.
In spite of its cancer detection shortcomings, Pap Smear screening is generally recognized as a practical and economical procedure for the early detection of cervical cancer.
However, there has been an increasing amount of controversy surrounding the Pap smear, regarding the quality of the sampling taken and consequently the accuracy of the results. The false negative rate for Pap smears (indicating nothing wrong, when there is a problem) has been shown to be approximately 30%.
In the early stages of cervical disease, abnormal cell exfoliation is slow and most abnormal cells are located below the surface or are trapped by a keratin barriers covering the cervical surface. In these circumstances, the Pap Smear screening process is a relatively insensitive indicator of cervical health due to inaccessibility of abnormal cells that are otherwise indicators of cancerous or pre-cancerous tissue.
If abnormalities (such as dysplasia, i.e., pre-cancerous cells, also called cervical intraepithelial neoplasia or low high-grade squamous intraepithelial lesion, etc.) are detected by Pap test, the patient is brought in a second time for a more detailed examination using a colposcope.
While the Pap Smear process is designed for initial screening, colposcopy and related procedures are generally used to confirm Pap Smear abnormalities and to grade cancerous lesions.
A colposcopy is the viewing of the cervix, vagina, and vulva through a high-powered microscope called a colposcope. The colposcope consists of a pair of binoculars attached to a stand and an illuminating unit. Direct examination through the colposcope allows the detection of abnormalities on the cervix that can not be seen with the naked eye. This procedure is performed with a vaginal speculum, which is used to hold open the vaginal cavity in order to allow viewing of the cervix. The cervix and vagina are swabbed with a diluted acetic acid (vinegar). The solution highlights areas (tissue which is thickened, such as cancer cells) by turning them white (instead of a normal pink color). Abnormal areas can also be identified by looking for a characteristic pattern made by abnormal blood vessels, which may indicate new growth, such as cancer.
If any abnormal areas are seen, the doctor will take a biopsy of the tissue. In a biopsy, a tiny sample of tissue will be removed from the area with a tweezer-like instrument. An endocervical scraping from the os (the opening in the middle of the cervix) may be taken as this is the area where often abnormal cells begin.
The effectiveness of this colposcopy procedure, which is a subjective visual assessment in detecting abnormalities, is believed to be approximately 85%, and this effectiveness is due in part to the greater amount of experience which physicians, who utilize this procedure, generally have. It should be noted, however, that the colposcope is difficult to use because of its complexity. Furthermore, it is not available in all medical facilities. It is also expensive and not at all portable.
Because colposcopy is a specialized procedure, requiring advanced and comprehensive training on a complicated and expensive apparatus, colposcopy is typically only performed on patients who have had an abnormal screening procedure (i.e., Pap smears or if the cervix looks abnormal during a routine naked eye examination).
It is well known that during routine gynecological examination it is impossible to diagnose diseases or other problems simply by looking at the cervix with the naked eye. A magnified view is necessary to find any abnormalities, or to show that cervical changes are not a cause for concern.
Therefore, the need for a portable magnification apparatus useful as a colposcope is present. Many attempts have been made heretofore to develop a portable colposcopic apparatus that would allow for the ready use of the colposcope as a screening tool, thereby increasing the opportunity for diagnosis and treatment.
U.S. Pat. No. 4,210,133 issued in 1980 to J. Castaneda discloses a vaginal colposcope for examination through the throat of the womb including a guide-tube and a microscope. The guide-tube is adjustably attached to a vaginal speculum and has its own illumination system, a graduated collar for focusing the microscope, and fine-adjustment clamps for preventing the accidental movements of the microscope. The microscope is adjustably positioned in the guide-tube so that it can focus on a plurality of microscopic fields without movement of the guide-tube. It has two illumination systems, one providing light for vision, the other an electronic flash for a photographic camera. The microscope can be removed from the stationary guide-tube, its objectives and oculars replaced by elements with different powers, and reinserted in the guide-tube to provide examination at variable magnifications.
This device is expensive, complicated in construction, and occupies the entire cavity of the speculum so that it cannot be used, e.g., for taking a biopsy during the observation.
U.S. Pat. No. 5,251,613 issued in 1993 to E. Adair discloses a tubular optical cervical colposcope (videoscope) insertable into a vaginal speculum for examining the cervix and vagina for cancerous lesions or other abnormalities. Although this instrument leaves some space for simultaneous use of other instruments such as a laser electrode, this videoscope is a complicated and expensive device, which is connected to a videochromator, video-control unit, light source, monitor, etc. The device requires expertise for using the instrument.
U.S. Pat. No. 5,479,293 issued in 1995 to T. Reed discloses a portable apparatus useful for close range physical examinations, in particular for use as a colposcope. The portable apparatus includes a stereoscopic optical unit, a main frame lens holder, an auxiliary frame lens holder, a light and mount therefor, a filter and mount therefor, and a support structure which allows the component parts to be maintained in precise optical alignment and allows the apparatus to be worn by a user in the manner of eyeglasses. These components are constructed and arranged to provide for an undistorted short focal length and magnification as necessary for clear close range visualization of body tissue.
A disadvantage inherent in the device of U.S. Pat. No. 5,479,293 and in all spectacle-like colposcopes consists in that this device is rather expensive, complicated in construction, and allows for observation of the zone of interest only at a distance.
Meanwhile, the use of a simplified one-lens colposcope may be extremely useful for preliminary screening of cervical cancer or other abnormalities. This was confirmed by the study described by Adtya Parasharu, et al. in xe2x80x9cBulletin of the World Health Organizationxe2x80x9d, 2000, V. 78 (8), pp. 964-967. The colposcopy was conducted with the use of a one-lens hand-held instrument consisting of a lens supported by a handle and an illumination device located under the lens. This inexpensive device was used for detecting precancerous lesions of the uterine cervix. The instrument, which is called xe2x80x9cMagnivisualizerxe2x80x9d, improved the detection rate of early cancerous lesions from 60%, for unaided visual inspection, to 95%. It is also permitted detection of 58% of cases of flow-grade dysplasia and 83% of cases of high-grade dysplasia. None of these cases were detectable by unaided visual inspection.
Although this device is not very expensive, it suffers the same disadvantages as the aforementioned spectacle-like colposcopes, i.e., the device cannot be inserted into a speculum and therefore cannot be used for observation of the zone of interest from a close distance.
The need, therefore, for a portable inexpensive magnification apparatus useful as a colposcope is present.
A primary object of the present invention is to provide a portable apparatus suitable for close range visual medical examinations at undistorted short focal lengths. It is another object of the present invention to provide a combination of a vaginal speculum with a single-lens colposcope for visual lens-aided detection of abnormal cells that may be indicators of cancerous or pre-cancerous tissue. It is another object to provide the aforementioned colposcope, which is simple in construction and inexpensive to manufacture. Still another object is to provide a conventional vaginal speculum with means for insertion and guiding of the aforementioned colposcope without violation of the speculum""s functions. Another object is to provide the aforementioned colposcope which is disposable. A further object is to provide the aforementioned colposcope with means for removing a liquid discharge from the speculum. Still another object is to provide a single-lens colposcope with means for insertion of rod-like tools into the vaginal speculum through the lens without obscuring the field of view through the lens.